android系統自帶下拉刷新控件的實現

android系統自帶的下拉刷新控件SwipeRefreshLayout位於android.support.v4.widget包下，實現步驟如下：

1.在布局文件中添加該控件，該控件一般作為父控件，而且只能包含有一個子控件，並且這個子控件是能夠滑動的，比如scrollview，listview等

2.實現OnRefreshListener接口，並重寫onRefresh函數

詳細代碼如下：

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v4.widget.SwipeRefreshLayout.OnRefreshListener;
import android.widget.TextView;


/**
 * MainActivity---系統下拉刷新控件的實現
 * @author seabear
 *
 */
public class MainActivity extends Activity implements OnRefreshListener{

	
	private SwipeRefreshLayout mSwipeRefreshLayout;
	private TextView mRandomText;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		mSwipeRefreshLayout = (SwipeRefreshLayout)this.findViewById(R.id.swipe_refresh);
		mSwipeRefreshLayout.setOnRefreshListener(this);
		
		mRandomText = (TextView)this.findViewById(R.id.random_text);
		
	}


	@Override
	public void onRefresh() {
		mSwipeRefreshLayout.setRefreshing(true);
		
		(new Handler()).postDelayed(new Runnable() {
			
			@Override
			public void run() {
				//3秒後停止刷新
				mSwipeRefreshLayout.setRefreshing(false);
				int num = (int)(Math.random() * 100 + 1);
				String s = mRandomText.getText().toString();
				s = s +   + num;
				mRandomText.setText(s);
				
			}
		}, 3000);
	}
}